GEOTHERMAL ENERGY RESOURCES OF INDIA: COUNTRY UPDATE

Abstract

All the geothermal provinces of India are located in areas with high heat flow and geothermal gradients. The heat flow and thermal gradient values vary from 75–468 mW/m 2 and 59–234°C respectively. Additional exploration studies and reservoir modelling have been carried out between 1995 and 1998 to understand the reservoir characteristics. Thermal gas discharges from several thermal provinces recorded high helium concentration varying from 0.5–6.9%. Gas data, together with heat flow and thermal gradient data, suggests the presence of granites and related intrusives with high U concentration (0.19–10.7%) in these provinces. Many such provinces are also best suited for HDR projects. High 4 He content in the thermal gases is obliterating the presence of primordial helium. Pilot power plants, commissioned at certain thermal discharge sites, proved the power generating capacity of these provinces. The estimated power generating capacity of the thermal discharges is about 10,600 MW. The available geophysical and geochemical data are sufficient to identify sites for undertaking deep drilling projects, and to commission binary power plants. Many independent power producers are keen to collaborate with foreign financial institutions to develop geothermal energy sources in rural India. With the existing environmental problems associated with coal based mega power projects, and with incentives given to develop non-conventional energy sources, the future of the Indian geothermal energy program is bright.